The exploits of Bravo Team are the subject of the 2002 prequel game, Resident Evil 0. Bravo headed out into the mountains by helicopter, only for a mechanical failure (the result of sabotage by Wesker) to force them to make an emergency landing. Trapped in the mountains, Bravo Team started its investigation anyway. Instead of heading to the Spencer mansion as Wesker had intended, however, the group discovered an abandoned military convoy, with documents inside suggesting the vehicle had been transporting Billy Coen, an accused murderer. With the soldiers escorting him now dead, Bravo started to suspect Coen might be the killer they were looking for.
While most of Bravo wound up at the Spencer mansion, rookie Bravo Team medic Rebecca Chambers, one of the player characters in Resident Evil 0, discovered a stopped train, the Ecliptic Express. Boarding it, she discovered that its passengers were all dead–and then started to come back to life as zombies, thanks to the T-Virus. Escaping the creatures, Rebecca discovered Coen hiding on the train. The pair decided to work together to survive whatever was happening.
Since the Spencer mansion facility was being destroyed, Wesker and Birkin had sent the train, filled with Umbrella researchers, to restart work at Marcus’s former facility, which hadn’t been in use since his death. But the Queen Leech, which was responsible for the other attacks and sabotage at Umbrella facilities in the area, attacked the train and killed everyone aboard. After the Ecliptic Express was stopped, Wesker and Birkin dispatched Umbrella soldiers to restart it, but they were attacked and killed by the Queen Leech too, sending the train careening toward the Umbrella facility. Rebecca and Billy managed to slow the train down, surviving the crash. The incident made it clear to Wesker and Birkin, finally, that Umbrella was being attacked–ostensibly by the dead James Marcus.
Rebecca and Billy eventually destroyed the Queen Leech and escaped, while Wesker and Birkin separately activated the facility’s self-destruct system and wiped out the T-Virus and the creatures there. Rebecca released Billy, whom she now believed was innocent, and maintained that he’d been killed. She went looking for the rest of Bravo Team; her search soon took her to the Spencer Mansion, where things got even worse.